Many pourable food products, such as fruit juice, still drinks, milk, wine, tomato sauce, etc., packed and sold in packages made of a paper- or carton-based packaging material exist. A typical example of this type of package is the parallelepipedic package known as Tetra Brik®, which is made by folding and sealing a web of laminated packaging material. The described packages are produced in fully automatic packaging machines such as for example Tetra Pak A3 packaging machine applying the form-fill-seal technology. Optionally the packages are of the type where a pre-manufactured sheet of the laminated packaging material are formed and filled, a typical example being marketed as Tetra Recart®
The packaging material in which the layer of barrier material comprises an electrically conductive material, for example an aluminium layer, is normally heat sealed by a so-called induction heat-sealing process, in which, eddy currents are induced in the aluminium layer, resulting in a localized heating and thus melting the heat-sealable polymeric material locally.
Conventionally the packages are heat-sealed using induction heat sealing inducing localized heating in a conductive material, e.g. the aluminium layer. Typically the sealing device comprises an inductor made of copper (Cu).
Typically, the induction sealing device, and therefore also the inductor, is exposed to high temperatures, high pressures and hydrogen peroxide in the packaging machine. This combination creates an aggressive environment which in certain applications causes rapid corrosion and wear of the inductor. Consequently, the sealing devices have to be replaced regularly, each replacement causing a stop in the production of packages.